Abstract: In an output buffer circuit, an input signal is transmitted through a bus by way of a latch circuit and a driver. A stable-state interval detector detects an interval during which the input signal remains in the same logical state. If the stable-state interval detected is relatively short, a drivability controller controls the drivability of the driver at a normal value. To the contrary, if the interval detected is relatively long, the controller increases the drivability of the driver. In general, if the stable-state interval of an input signal is relatively long, then the time taken for the subsequent logical state transition of the signal tends to be longer as compared with a signal having a shorter stable-state interval. However, if the drivability of the driver is increased, then the state transition time is shortened, and substantially equalized with that of a signal having a relatively short stable-state interval. As a result, signal skewing can be minimized.
Type:
Grant
Filed:
January 21, 1999
Date of Patent:
June 6, 2000
Assignee:
Matsushita Electric Industrial Co., Ltd.
Abstract: In a method of manufacturing a semiconductor device, an insulating film having an opening is formed on an amorphous film 103 containing silicon therein. After catalytic elements are introduced from the opening, the amorphous film 103 is crystallized. Thereafter elements (phosphorus) selected from Group XV are introduced from the opening, and then a heat treatment is conducted to obtain a film having crystallinity. Thereafter, a portion of the film containing silicon into which the catalytic elements and phosphorus is introduced are removed.
Type:
Grant
Filed:
July 21, 1998
Date of Patent:
May 23, 2000
Assignee:
Semiconductor Energy Laboratory Co., Ltd.
Abstract: In an annealing process in which laser light is irradiated to a semiconductor thin film, a refractive index of the semiconductor thin film after laser light irradiation is measured and conditions for the next laser light irradiation are adjusted based on the measured refractive index value. For example, laser light irradiation conditions are adjusted so that semiconductor thin films always have the same refractive index. As a result, the annealing can be performed under the same conditions at every laser light irradiation even if the laser light irradiation conditions vary unavoidably. For a crystalline silicon film, if the refractive index is larger than 3.5, then a thin-film transistor using such as film has desired crystallinity and flatness properties such that a field-effect mobility is greater than 100 cm.sup.2 /Vsec.
Type:
Grant
Filed:
May 26, 1995
Date of Patent:
May 9, 2000
Assignee:
Semiconductor Energy Laboratory Co., Ltd.
Abstract: A semiconductor device capable of maintaining good temperature compensation and reducing manufacture costs of SEPP connecting NPN and PNP power transistors and temperature compensating and biasing circuits. A first semiconductor device has an ordinary bias diode formed on the same semiconductor substrate as an NPN power transistor. A second semiconductor device has one or a plurality of Schottky barrier type diodes formed on the same semiconductor substrate as a PNP power transistor. The forward voltage drop V.sub.1 of the diode is set to an arbitrary constant value smaller than E exclusive of about E/2, and the total forward voltage drop V.sub.2 of the Schottky barrier diode or diodes is set to a predetermined value of about (E-V.sub.1), where E is a total forward voltage drop between the bases and emitters of the NPN and PNP power transistors.
Abstract: A semiconductor device having an active layer comprising crystalline silicon, said active layer comprising a first layer comprising crystalline silicon formed on an insulating surface and a second layer comprising crystalline silicon formed on said first layer, wherein said first layer contains a metal element at a first concentration while said second layer is free from said metal element or contains said metal element at a second concentration which is lower than said first concentration.
Type:
Grant
Filed:
March 11, 1998
Date of Patent:
April 11, 2000
Assignee:
Semiconductor Energy Laboratory Co., Ltd.
Abstract: Both the distortion characteristic and the through rate characteristic of an operational amplifier are excellently retained over a wide range of a supply voltage. While an operating current of a differential circuit is controlled by a first current source circuit, an operating current of a level shift circuit is controlled by a second current source circuit. The first current source circuit controls the operating current to be substantially constant against a change of the supply voltage, so that the through rate characteristic of the operational amplifier can be good over a predetermined range of the supply voltage. The second current source circuit controls the operating current so that a difference between the supply voltage and a level shift voltage can be substantially constant against the change of the supply voltage so as not to degrade the distortion characteristic of the operational amplifier over the predetermined range of the supply voltage.
Type:
Grant
Filed:
January 28, 1999
Date of Patent:
April 11, 2000
Assignee:
Matsushita Electric Industrial Co., Ltd.
Abstract: In a solar cell including a photoelectric conversion layer 14 disposed on a flexible substrate 11 and constituted by a laminated layer of non-single crystalline silicon thin films, the flexible substrate 11 has a coefficient of linear thermal expansion of is 2.0 ppm to 10.0 ppm. By this, the coefficient of linear thermal expansion of the flexible substrate 11 and that of the photoelectric conversion layer 14 become close to each other, so that warp and deformation during manufacturing steps and after the steps are decreased. Further, since stress applied to the photoelectric conversion layer 14 is also lessened, the photoelectric conversion efficiency can be increased.
Type:
Grant
Filed:
April 22, 1998
Date of Patent:
March 21, 2000
Assignees:
Semicondutor Energy Laboratory Co., Ltd., TDK Corporation
Abstract: A holder holds a mini-disc cartridge and mounts the disc on a turntable. An optical pickup transport holding an optical pickup for applying a laser spot to a signal record track of the disc is movably supported by a guide rod. A magnetic head contacts the disc and applies a magnetic field to the back surface of the disc where the laser spot is applied. A switch judges whether the data record to the disc is to be permitted. The magnetic head is pushed against the disc only when the mounted disc is permitted to record data and the data record is to be performed.